Adjustable valve tappet



C. H. NICKELL ADJUSTABLE VALVE TAPPET Sept. 4, 1951 Filed April 24, 1946 FIG. 1

2 Sheet-Sheet 1 FIG. 3

t I I4 I 42.-

I N YEN FUR,

Q. H. MECKELL ATTORNEY p 1951 c. H. NICKELL 2,567,078

ADJUSTABLE VALVE TAPPET Filed April 24, 1946 2 Sheets-Sheet 2 35 lfllllllllllll lllllll Z FIG. 6

INVENTORH C- H NECKELL ATTORNEY iatented Sept. 4, 1951 UNITED STATES PATENT OFFICE ADJUSTABLE VALVE TAPPET Claude H. Nickell, New Castle, Ind.

Application April 1946, Serial No. 664,665

This invention relates to improvements in valve tappets for internal combustion engines and particularly to an improved hollow or barrel type tappet.

Hollow cylindrical valve tappets have been in use for some time as components of internal combustion engines, particularly automobile engines, and a large amount of work has been done toward perfecting this type of tappet. In spite of the work already done the hollow or barrel type tappet is still subject to various defects which the present invention eliminates in a practical and economic manner.

Among such defects are inadequate lubrication of the bearing surfaces of the tappet and tappet guide, a tendency for the tappet adjustment to change during operation, and unnecessarily high manufacturing cost.

It is therefore among the objects of the present invention to provide an improved-engine valve tappet of hollow cylindrical construction having tappet clearance adjusting means associated with the tappet in a manner such that the adjustment can be easily made and the parts will be automatically locked in adjusted position, the tappet bearing surfaces will be provided with adequate and continuous lubrication even during the period immediately following starting of the engine while the engine oil pressure is building up, and the tappets can be manufactured at very low cost.

A further object resides in the provision of an improved hollow cylindrical valve tappet which may be used to replace worn or unsatisfactory tappets provided as original components'of an engine and which will accurately fit the tappet guides and the space between the valve cam and valve stem occupied by the original tappet.

Further objects and advantages of the invem tion will be apparent from the following description taken in conjunction with the accom' panying drawings, wherein:

2 Claims. (Cl. 123- 90) Fig. l is a vertical sectional view through a tappet illustrative of the invention and a fragmentary portion of the tappet guide;

Fig. 2, a top plan view of the tappet illustrated in Fig. 1;

Fig. 3, an elevational view of the tappet illustrated in Fig. 1;

Fig. 4, a diagrammatic plan view of the tappet showing the manner of applying an adjusting tool thereto;

Fig. 5, a vertical sectional view of a modified form of tappet;

Fig. 6, a sectional view similar to Fig. 5 of a 2 further modified form of tappet illustrative of the invention; and

Fig. 7, a diagrammatic view illustrating the manner in which the locking threads are provided on the tappet adjusting screws.

With continued reference to the drawings and particularly to Figs. 1, 2 and 3, the tappet is of a hollow cylindrical or barrel type and comprises a cylindrical body portion [0 adapted to be slidably mounted in a tappet guide which may comprise a flangedsleeve or bushing ll pressedinto a boss l2 formed as an integral part of the engine crank case.

The member Hlmay be formed of tubular stock, either drawn or welded, of suitable steel that can be provided with a hardened outer surface to resist wear. An alloy steel may be used if desired or a cheaper medium carbon steel may be used and subjected to carburizing and heat treating processes known to the art to provide a hardened, wear resistant surface.

At substantially its mediumlength position this tubular body is provided externally with a circumferential groove [3 to carry lubricant for the bearing between the tappet and the guide. The body is also provided with a plurality of apertures extending therethrough, one group of substantially circumferentially' arranged apertures, as indicated at [4, being disposed at one side of the groove l3 and a second group, as indicated at l5, being disposed at the opposite side of the groove, both groups of apertures being positioned substantially midway between the groove and the adjacent end of the tubular body portion l0.

One end of the cylindrical body portion I0 is closed by a plate-like member 16 provided with an annular shoulder H which overlies the end of the tubular portion l0 and is flush with the outer surface of the tubular member. Inwardly of the shoulder theclosure member I 6 fits within the tubular member, and the inner portion of the end member l6 may be coned outfas indicated at l9, to reduce the'weight of the member. The member I6 has its outer surface hardened to provide a bearing for the cam 20 and is secured to the tubular portion II] by a suitable welding or brazing operation.

While it provides a more economical use of materials to form the members In and I6 separately and secure them together in operative relationship, other methods may be used without exceeding the scope of the invention, as for example drilling a solid bar to provide the members In and I6 as an integral structure.

The opposite end of the tubular member In is closed by a closure member 2| which is also provided with an annular shoulder 22 which overlies the associated end of the tubular portion and is flush with the external surface thereof. Adjacent the shoulder the closure member has a circumferential flange 23 which extends into the tubular member to locate the closure member permanently with respect to the tubular member, the inner portion of the closure member being cut away substantially'back to theplane of the shoulder 22, as indicated at 24. The closure member has a thickened center portion 25 provided with a central, screw threaded aperture 26 V and surrounded by an upstanding circumferen tial flange 27 which has substantially the same inner and outer diametrical dimensions as the tubular portion It. This flange is provided with a plurality of angularly spaced slots or tool engaging recesses 28 for the Ireception of the fingers 29 of a suitable tool such as the spanner wrench 30, particularly illustrated in Fig. 4. v

The tappet is provided with an adjusting screw 3| and the spanner wrench is used to hold the tappet against rotation during adjustment of the screw by a suitable tool such as an ordinary open end wrench, not illustrated.

Adjusting screw 3| has a tubular, externally screw threaded shank portion 32 and a polygonal head portion 33 which may conveniently be in the form of a conventional hexagonal head, as illustrated in Fig. 2.

As is diagrammatically illustrated in Fig. 7, the threads on the adjusting screw are formed at a slightly different angle from the threads in the aperture of the end closure member 2|, the threads in the aperture being based on a straight cylindrical surface while the threads on the adjusting screw are based on a somewhat conical surface, the dimensions of which are such that the diameter of the cone at the midlength point of the threaded area is substantially the same as the base diameter of the threads in the aperture. With this arrangement of threads when the adjusting screw is threaded into the end closure aperture, the tubular shank of the adjusting screw is slightly distorted, the threads thereof being pulled inwardly about a point on the axis of the screw shank and located at substantially the center of the threaded length of the shank. The distortion of the screw shank is within the elastic limits of the metal of this tubular shank so that the screwed shank acts as a spring resiliently forcing the threads into locking engagement. The direction of distortion is such that end pressure on the adjusting screw tends to tighten the threads and prevent rotation of the adjusting screw relative to the tappet during operation of the engine.

The outer surface of the bottom closure mem ber I6 and the top surface of the screw head 33 are both machined at right angles to the axis of the tappet and preferably are both hardened to provide wearing surfaces for the cam and the lower end of the valve stem engaged by the top surface of the adjusting screw head. V

The apertures I l and 15 in the tubular portion II] are so arranged that the apertures I are normally below the lower end of the tappet guide I I and within theengine crankcase where they receive lubricating oil splashed against the crankcase walls by the engine crankshaft. Lubricating oil is thus splashed through these open ports into the interior of the tappet and as the tappet is rapid ved, up a d d n b ac u i n Of 4 the cam 20, the lubricant within the tappet is splashed through the upper apertures or ports I4 to the surface of the valve guide II. As the lower ports I5 are located somewhat above the bottom end closure member IS, a receptacle is provided in the bottom of the tappet which always contains lubricating oil and, as soon as operation of the engine begins, this oil will be splashed through the upper ports to the surface of the guide, thus providing lubricant for the guide even during the period immediately after starting the engine and before the engine oil pressure has built up to its normal operating value.

The arrangement of the adjusting screw and the locking threads provided between this screw and the tappet permit rapid and easy adjustment of the tappet clearance by the use of only two adjusti'ng tools instead of three tools required in those arrangements wherein the adjusting screw is locked into position by a lock nut. The locking threads, as described above, hold the adjusting screw in its adjusted position as efiectively as the lock nuts previously used.

The modified tappet illustrated in Fig. 5 is similar in construction to the tappet just described except for a slightly difierent shape of the end closure members. In this modified arrangement the bottom end closure member Ilia is formed as a simple flat disk with parallel surfaces and an upstanding circumferential flange 35 on one side thereof spaced inwardly from the periphery of the member a distance equal to the thickness of the tubular portion I8.

The tubular portion is provided with the lower ports I5 but the upper sets of the ports in the tubular portion are omitted. The top closure member comprises a concentric apertured boss 36 internally threaded and surrounded by a web portion 31 and an integral peripheral flange 38 parallel to and concentric with the boss. At its inner end the flange 38 is recessed, as indicated at 39, to provide a seat for the corresponding end of the tubular portion IEI and is provided in its cylindrical portion with angularly spaced ports or apertures 40. The web portion 31 is provided with ports or apertures 4I- through which lubricating oil may pass from the interior of the tappet. The apertures ,40 serve both as lubricating ports and as tool engaging recesses. Lubricant passing through these ports while they are above these guides will be deflected by the valve tappet cover plates of the engine and returned to the space around the top of the guides from which it will flow back to the engine crankcase.

In the modified form of tappet shown in Fig. 6, the construction is also similar to that shown in Figs. 1, 2 and 3 and described above.' In this modified arrangement, however, the lower 010 sure member IE2) is formed of hard alloy metal and may be made of thin-walled stock, thereby materially reducing the weight of the tappet. It has a circumferential flange 42 providing a seat for the lower end of the tubular portion ID in the same manner as the flange 35 of'Fig. 5. The upper closure member 43 is provided as a thickwalled disk having substantially parallel sides with a circumferential flange 44 on one s'ideproviding a seat for the associated. .end of tubular member I0 and having slots or toolengaging recesses 45 milled into its upper surface to provide tool engaging seats. This construction omits the outer flange 21 of Figs. 1 and 2 and while it provides an upper end closure member having somewhat more material, it would require fewer machining operations and would be entirely satisfactory, particularly as sufficient material is omitted from the lower closure member to compensate for the increased weight of the upper member.

In both of the modified forms shown in Figs. 5 and 6, the adjusting screw and locking thread arrangement is the same as that described above in connection with Figs. 1 and 7. The form shown in Fig. 6 also has the upper and lower ports H and I5 as in Fig. 1 located at opposite sides of the external groove 13.

This arrangement provides an adjustable hollow or barrel type tappet which is easy to adjust and will remain in properly adjusted condition during use, which is adequately lubricated at all times, which is light in weight and economical to manufacture.

- It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. A barrel type valve tappet comprising a tubular cylindrical portion having an external groove at substantially its midlength and two sets of ports therethrough, one set located at substantially the mid point between each end and said groove, a pair of disk-shaped end closure members for said cylindrical portion, each having a shouldered seat for the corresponding ends of the tubular portion, one of said members having a flat hardened outer surface for contact with the valve operating cam and the other having a central screw threaded aperture and tool engaging recesses; and an adjusting screw threaded into said aperture, said ports being so disposed that the lower set is inside the engine crankcase to receive lubricating oil and so that the lower portion of said tappet retains lubricating oil therein and the upper set directs lubricating oil from said tappet onto the bearing surfaces of the tappet and tappet guide.

2. A barrel type valve tappet comprising a tubular cylindrical portion having an external circumferential groove at substantially its midlength and apertures therethrough providing a set of ports between said groove and the lower end of said portion, said ports being disposed within the engine crankcase to receive lubricating oil a pair of disk-shaped end closure members for said cylindrical portion each having a shouldered seat for the corresponding ends of the tubular portion, the lower one of said members having a flat, hardened outer surface for contact with the valve operating cam, and the other having a central apertured boss provided internally with screw threads, a cylindrical flange having its outer surface flush with the outer surface of said cylindrical portion and having apertures therethrough constituting lubricant ports and tool engaging recesses, and an apertured web between said central boss and said flange.

CLAUDE H. NICKELL.

REFERENCES CITED The following references are of record in the me of this patent:

UNITED STATES PATENTS Number Name Date 1,682,821 Woolson Sept. 4, 1928 1,957,784 Johnson May 8, 1934 2,178,724 Hoern Nov. 7, 1939 2,181,965 Daisley Dec. 5, 1939 

